阅读以下说明和C语言函数，将应填入(n)处的语句写在对应栏内。

【说明】

本程序从正文文件text.in中读入一篇英文短文，统计该短文中不同单词及出现次数，并按词典编辑顺序将单词及出现次数输出到正文文件word.out中。

程序用一棵有序二叉树存储这些单词及其出现的次数，边读入边建立，然后中序遍历该二叉树，将遍历经过的二叉树上的结点内容输出。

【函数】

include ＜stdio.h＞

include ＜malloc.h＞

include ＜ctype.h＞

include ＜string.h＞

define INF "text.in"

define OUTF "word.our'

typedef struct treenode {

char *word;

int count;

struct treenode *left, *right;

} BNODE;

int getword(FILE *fpt, char *word)

{ char c;

c=fgetc(tpt);

if (c==EOF)

return 0;

while(!(tolower(c)＞= 'a' && tolower(c)＜= 'z'))

{ c=fgetc(fpt);

if (c==EOF)

return 0;

} /* 跳过单词间的所有非字母字符 */

while(tolower(c)＞= 'a' && tolower(c)＜= 'z')

{ *word++=c;

c=fgetc(fpt);

}

*word='\0';

return 1;

}

void binary_tree(BNODE **t, char *word)

{ BNODE *ptr, *p; int compres;

p=NULL;

(1);

while (ptr) /* 寻找插入位置 */

{ compres=strcmp(word, ptr-＞word);/* 保存当前比较结果 */

if (!compres)

{ (2); return;}

else

{ p=ptr;

ptr=compres＞0 ? ptr-＞right: ptr-＞left;

}

}

ptr=(BNODE *)malloc(sizeof(BNODE));

ptr-＞left=ptr-＞right=NULL;

ptr-＞word=(char *)malloc(strlen(word)+1);

strcpy(ptr-＞word, word);

(3);

if (p==NULL)

*t=ptr;

else if (compres＞0)

p-＞right=ptr;

else

p-＞left=ptr;

}

void midorder(FILE *fpt, BNODE *t)

{ if (t==NULL)

return;

midorder(fpt,(4));

fprintf(fpt, "%s %d\n", t-＞word, t-＞count);

midorder(fpt, t-＞right);

}

void main()

{ FILE *fpt; char word[40];

BNODE *root=NULL;

if ((fpt=fopen(INF, "r"))==NULL)

{ printf("Can't open file %s\n", INF);

return;

}

while(getword(fpt, word)==1)

binary_tree((5));

fclose(fpt);

fpt=fopen(OUTF, "w");

if (fpt==NULL)

{ printf("Can't open fife %s\n", OUTF);

return;

}

midorder(fpt, root);

fclose(fpt);

}